color and durability of ink-jet ink sets with added latex

ABSTRACT

The present disclosure is directed to ink sets and related methods for ink-jet printing on media, such as low-porous or non-porous print media. The inks and ink sets provide good chroma as well as good durability.

BACKGROUND

Inks used in printing on low-porous or non-porous print media, such asvinyl, provide a challenge with respect to generating an image with highdurability, high chroma, and good lightfastness simultaneously withoutthe need for an additional lamination step. Although lamination canprovide improved durability and color gamut, it results in added expense(both through added materials and increased scrap and incremental laborcosts) and slower turn around time. One approach to formulating inks foruse in low-porous or non-porous media to achieve the above-describedcharacteristics has been by increasing the pigment concentration in theink. Unfortunately, this can decrease the durability of the image.Another approach has been to use higher chromatic pigments.Unfortunately, such pigments typically have much lower lightfastness andthus are not desirable for outdoor graphics, a common use for low-porousor non-porous media. A third approach to achieving the above-describedcharacteristics has been adding solution resins. The addition ofsolution resins suffers from the drawback that these materials oftenincrease the viscosity of the ink, thereby causing the inks to hit theirviscosity limit and rendering the inks unreliable in many ink-jetprintheads.

Accordingly, investigations continue into developing ink and ink setformulations that are capable of providing high durability, high chroma,and good lightfastness when printed on low-porous or non-porous mediawithout the need for lamination.

DETAILED DESCRIPTION

Before the present invention is disclosed and described, it is to beunderstood that this disclosure is not limited to the particularstructures, process steps, or materials disclosed herein, but isextended to equivalents thereof as would be recognized by thoseordinarily skilled in the relevant arts. It should also be understoodthat terminology employed herein is used for the purpose of describingparticular embodiments only and is not intended to be limiting.

In describing and claiming the present disclosure, the followingterminology will be used in accordance with the definitions set forthbelow.

It is noted that, as used herein, the singular forms of “a,” “an,” and“the” include plural referents unless the context clearly dictatesotherwise. Thus, for example, reference to “an ink” includes one or moreof such inks, reference to “an amount of pigment” includes reference toone or more amounts of pigments, and reference to “the ink set” includesreference to one or more ink sets.

As used herein, “vehicle,” “liquid vehicle” or “ink vehicle” refers tothe liquid fluid in which colorant is placed to form an ink. Liquidvehicles are well known in the art, and a wide variety of liquidvehicles may be used in accordance with embodiments of the presentdisclosure. Such ink vehicles may include a mixture of a variety ofdifferent agents, including without limitation, surfactants, solvents,co-solvents, buffers, biocides, viscosity modifiers, sequesteringagents, stabilizing agents, and water. The liquid vehicle can also carryother additives such as latexes, polymers, UV curable materials, and/orplasticizers, in some embodiments.

As used herein, “pigment” generally includes solid pigment colorants.Pigments can be dispersed in a liquid vehicle with a separate dispersingagent, or can have dispersing agent attached to its surface, e.g., smallmolecule or polymeric dispersing agents. As used herein, “ink” refers toa single liquid vehicle that contains a pigment, and in accordance withembodiments of the present disclosure, the inks can also include latexpolymer solids.

As used herein, the term “set” refers to a set of inks, whether packagedor made available as part of a set, or packaged and made availableseparately for use with other members of the set.

As used herein, the term “fastness” refers to that property of theprinted image which helps maintain its color characteristics (e.g., Hue,Value, Chroma) which may include light fastness, ozone fastness, waterfastness, or a combination thereof.

As used herein, the term “ramp” or “color ramp” refers to printing ofinks or ink sets at various densities ranging from very low densities ofink to very high densities of ink. For example, with a black ink, acolor ramp can be based on an L* value such that the L* value of a givencolor ranges from about 0 (black or near black) to about 95 (very lightcolor). With a color (non-black) ink, color ramps can range from a C* orchroma of 0 to 130 depending upon the ink color and composition. Rampsare typically printed as diagnostic to determine the properties ofseveral representative “color” points between two end points. Forexample, a color ramp might include 5 to 20 printed squares (or othershapes) which are relatively evenly spaced in color density, e.g., amagenta color ramp might include printed squares at C* values of 10, 20,35, 50, 70, 85, and 95.

The terms “low-porous media” or “non-porous media” each refer to printmedia which has a Bristow Test of less than 2 ml/m² at a contact time ofless than 0.5 s. The Bristow Test is known in the art and is summarizedbelow. A test specimen of defined dimensions is affixed to the smoothrim of a wheel free to rotate at a defined constant speed in contactwith a stationary test fluid applicator pressing against the testspecimen with a defined pressure. The test fluid applicator consists ofa test solution storage compartment affixed above a 1 by 15-mm testfluid delivery slot, the slot being positioned so that the longdimension is perpendicular to the direction of rotation of the rim ofthe wheel, and parallel to the wheel axis. A defined quantity of testfluid is placed through the fluid reservoir, onto the fluid deliveryslot. With the wheel with the test specimen affixed rotating at constantspeed, the test solution applicator is brought into contact with therotating test specimen and held in place under defined pressure. Thetest fluid is transferred from the test solution applicator onto thetest specimen in a band whose width, controlled by the applicator slotwidth is approximately 15 mm, and whose length is function of theabsorptive characteristics of the test fluid interaction with the testspecimen under the defined test conditions. The amount of liquidabsorbed per unit area of test specimen is calculated from the volume oftest fluid originally placed in the applicator, and the average widthand length of the band created on the test specimen by the transferredtest fluid. The time available for the liquid absorption is calculatedfrom the volume of test fluid originally placed in the applicator andapplicator geometry.

As used herein, “self-dispersed,” “dispersant-functionalized” or aderivation thereof generally refers to pigments that have beenfunctionalized with a dispersing agent, such as by chemical attachmentof the dispersing agent to the surface of the pigment. The dispersingagent can be a small molecule or a polymer or oligomer. The dispersingagent can be attached to such pigments to terminate the outer shell ofthe pigment with a charge, thereby creating a repulsive nature thatreduces agglomeration of pigment particles within the liquid vehicle.

As used herein, “latex,” “latex polymer,” or “latex particles” refer tothe polymeric masses synthesized from individual monomers, which can bedispersed in a liquid vehicle forming a latex dispersion. The term“latex” generally refers to liquid and polymeric particles that aredispersed within the liquid. However, when a latex is formulated withinan ink, the liquid becomes part of the liquid vehicle of the ink, andthus, latex polymer can be described based on the latex particle orlatex polymer solids that remain dispersed in the liquid vehicle. It isnoted that in accordance with some embodiments of the present invention,the solids of a latex polymer in some inks can increase the absorbanceof ink at from 0.1% to 10% compared to an identical ink devoid of thesolids of the latex polymer.

As used herein, the term “about” is used to provide flexibility to anumerical range endpoint by providing that a given value may be “alittle above” or “a little below” the endpoint. The degree offlexibility of this term can be dictated by the particular variable andwould be within the knowledge of those skilled in the art to determinebased on experience and the associated description herein.

Unless otherwise specified, the path length for the UV absorbancemeasurements set forth herein is 1 cm.

As used herein, a plurality of items, structural elements, compositionalelements, and/or materials may be presented in a common list forconvenience. However, these lists should be construed as though eachmember of the list is individually identified as a separate and uniquemember. Thus, no individual member of such list should be construed as ade facto equivalent of any other member of the same list solely based ontheir presentation in a common group without indications to thecontrary.

Concentrations, amounts, and other numerical data may be expressed orpresented herein in a range format. It is to be understood that such arange format is used merely for convenience and brevity and thus shouldbe interpreted flexibly to include not only the numerical valuesexplicitly recited as the limits of the range, but also to include allthe individual numerical values or sub-ranges encompassed within thatrange as if each numerical value and sub-range is explicitly recited. Asan illustration, a numerical range of “about 1 wt % to about 5 wt %”should be interpreted to include not only the explicitly recited valuesof about 1 wt % to about 5 wt %, but also include individual values andsub-ranges within the indicated range. Thus, included in this numericalrange are individual values such as 2, 3.5, and 4 and sub-ranges such asfrom 1-3, from 2-4, and from 3-5, etc. This same principle applies toranges reciting only one numerical value. Furthermore, such aninterpretation should apply regardless of the breadth of the range orthe characteristics being described.

The present disclosure is directed to inks and ink sets used for ink-jetprinting (e.g. piezoelectric or thermal ink-jet printing). In oneembodiment, the ink sets of the present disclosure are formulated foruse in thermal ink-jet printing systems such as the DESKJET®,DESIGNJET®, PHOTOSMART®, or other similar family of printers, which arecommercially available from the Hewlett-Packard Company of Delaware. Theinks of the present disclosure are useful for printing on low-porous ornon-porous print media such as pressure-sensitive adhesive backedflexible vinyl media commonly used for outdoor graphics, as well asother low-porous and non-porous print media. Examples of such mediainclude, but are not limited to Avery 1005, Avery 3000, Avery 3100,Avery MPI 1005 EZ, Avery MPI 4002, Ultraflex Normandy Pro, UltraflexJetFlex FL, Ultraflex Strip Mesh, Ultraflex BIOflex, Verseidag Front LitStandard Easy P/N 7945, LG Bannux 1100, 3M ScotchCal, Mactac JT5829,MacTac JT5929p, Intelicoat SBL-7SIJ, Intelicoat GFBL5SIJ, 3M ControltacPlus IJ180C-10, 3M ScotchLight, Flexcon See Through Sign Vision, DyksonJet 220, C2S Sterling Ultra Gloss and the like.

The present disclosure is also related to inks, ink sets, and associatedmethods and systems used for ink-jet printing (e.g. piezoelectric orthermal ink-jet printing). The ink sets of the present disclosure caninclude at least two inks selected from the group of black, cyan,magenta, and yellow. Each of the inks is independently described below,but such inks are typically present in ink sets, e.g., cyan, magenta,and yellow; cyan, black, and optionally magenta and yellow; etc.

The black ink for use in the ink sets of the present disclosure,hereinafter referred to as “black ink,” can include from 0.25 wt % to 3wt % solids of a black pigment and from 4 wt % to 15 wt % solids of alatex polymer. When the black ink is diluted to 1:2,500 dilution inwater, it has a UV absorbance of 0.040 to 0.468 at about 500 nm. In oneembodiment, a 1:2,500 dilution of the black ink can have an absorbanceat 500 nm of 0.16 to 0.36. In another embodiment, the black ink cancomprise 1.25 wt % to 2 wt % solids of the black pigment and the latexpolymer can be present in the black ink at from 5 wt % to 8 wt % bysolids.

The black pigment can be any commercially available black pigment thatprovides acceptable optical density and print characteristics. Suchblack pigments (Color Index Pigment Black 7, CI PB1 7) can bemanufactured by a variety of known methods such as channel methods,contact methods, furnace methods, acetylene methods, or thermal methods,and are commercially available from such vendors as Cabot Corporation,Columbian Chemicals Company, Evonik, and Mitsubishi. For example,commercially available carbon black pigments include Cabot: Monarch™1400, Monarch™ 1300, Monarch™ 1100, Monarch™ 1000, Monarch™ 900,Monarch™ 880, Monarch™ 800, and Monarch™ 700, Cab-O-Jet™ 200, Cab-O-Jet™300, Black Pearls™ 2000, Black Pearls™ 1400, Black Pearls™ 1300, BlackPearls™ 1100, Black Pearls™ 1000, Black Pearls™ 900, Black Pearls™ 880,Black Pearls™ 800, Black Pearls™ 700; the following are available fromColumbian: Raven 7000, Raven 5750, Raven 5250, Raven 5000, and Raven3500; the following are available from Evonik: Color Black FW 200, ColorBlack FW 2, Color Black FW 2V, Color Black FW 1, Color Black FW 18,Color Black S 160, Color Black FW S 170, Special Black 6, Special Black5, Special Black 4A, Special Black 4, Printex U, Printex 140U, PrintexV, and Printex 140V, and combinations thereof.

The cyan ink for use in the ink sets of the present disclosure,hereinafter referred to as “cyan ink,” can include from 0.25 wt % to 3wt % solids of a cyan pigment and from 4 wt % to 15 wt % solids of alatex polymer. When the cyan ink is diluted 1:2,500 in water it has a UVabsorbance of 0.048 to 0.592 at its absorbance peak found at from 610 nmto 630 nm. In one embodiment, a 1:2,500 dilution of the cyan ink canhave an absorbance peak at 610 to 630 nm of 0.16 to 0.38. In anotherembodiment of the present disclosure, the cyan pigment in the cyan inkcan comprises 1.25 wt % to 2 wt % solids of the cyan pigment and thelatex polymer can be present in the cyan ink at 5 wt % to 8 wt % bysolids.

The cyan pigment can be any commercially available cyan pigment thatprovides acceptable optical density and print characteristics.Non-limiting examples of cyan pigments include BASF pigments such asHeliogen® Blue L 6901F, Heliogen® Blue NBD 7010, Heliogen® Blue K 7090,Heliogen® Blue L 7101F, Paliogen® Blue L 6470; Heuback pigments such asHeucophthal® Blue G, other pigments such as CI Pigment Blue 15, CIPigment Blue 15:1, CI Pigment Blue 15:2, Pigment Blue 15:3, and PigmentBlue 15:4, and combinations thereof.

The magenta ink for use in the ink sets of the present disclosure,hereinafter referred to as “magenta ink,” can include from 0.75 wt % to5 wt % solids of a magenta pigment and 4 wt % to 15 wt % solids of alatex polymer. When the magenta ink is diluted 1:2,500 in water it has aUV absorbance of 0.068 to 0.468 at its absorbance peak found at from 520nm to 555 nm. In one embodiment, a 1:2,500 dilution of the magenta inkcan have an absorbance peak at 520 to 555 nm of 0.16 to 0.36. In anotherembodiment of the present disclosure, the magenta ink can comprise 2.25wt % to 4.0 wt % solids of the magenta pigment and the latex polymer canbe present in the magenta ink at 5 wt % to 8 wt % by solids.

The magenta pigment can be any commercially available magenta pigmentthat provides acceptable optical density and print characteristics.Non-limiting examples of magenta pigments include CI Pigment Red 5, CIPigment Violet 19, CI Pigment Red 7, CI Pigment Red 12, CI Pigment Red48:1-5, Pigment Red 57:1-5 CI Pigment Red 112, CI Pigment Red 122,pigments by Ciba-Geigy such as Irgalite® Rubine 4BL, Monastral® Magenta,and Monastral® Scarlet; pigments by Mobay such as Quindo® Magenta andIndofast® Brilliant Scarlet; and pigments by Hoechst such as Hostaperm®Scarlet GO and Permanent Rubine F6B; others pigments such as Pigment Red122, Pigment Red 192, Pigment Red 202, Pigment Red 206, Pigment Red 207,Pigment Red 209, Pigment Red 43, Pigment Red 194, Pigment Red 216 andPigment Red 226, Pigment Red 123, Pigment Red 149, Pigment Red 179,Pigment Red 190, Pigment Red 189, Pigment Red 224, Pigment Red 86,Pigment Red 87, Pigment Red 88, Pigment Red 181, Pigment Red 198, CIPigment Red 264, and combinations thereof.

The yellow ink for use in the ink sets of the present disclosure,hereinafter referred to as “yellow ink,” can include from 1 wt % to 4.5wt % solids of a yellow pigment and 4 wt % to 15 wt % solids of a latexpolymer. When the yellow ink is diluted 1:2,500 in water it has a UVabsorbance of 0.176 to 0.784 at its absorbance peak found at from 380 nmto 430 nm. In one embodiment, a 1:2,500 dilution of the yellow ink canhave an absorbance peak at 380 to 430 nm of 0.38 to 0.68. In oneembodiment of the present disclosure, the yellow ink can comprise 2.5 wt% to 4.5 wt % solids of the yellow pigment and the latex polymer can bepresent in the yellow ink at 5 wt % to 8 wt % by solids.

The yellow pigment can be any commercially available yellow pigment thatprovides acceptable optical density and print characteristics.Non-limiting examples of yellow pigments include pigments by Hoechstsuch as Permanent Yellow DHG, Permanent Yellow GR, Permanent Yellow G,Permanent Yellow NCG-71, Permanent Yellow GG, Hansa Yellow RA, HansaBrilliant Yellow 5GX-02, Dalamar® Yellow YT-858-D, Hansa Yellow X,Novoperm® Yellow FGL, Hansa Brilliant Yellow 10GX, Permanent YellowG3R-01, Hostaperm® Yellow H4G, Hostaperm® Yellow H3G, and Novoperm®Yellow HR; pigments by Ciba-Geigy such as Chromophtal® Yellow 3G,Chromophtal® Yellow GR, Chromophtal® Yellow 8G, and Irgazin® Yellow 5GT;and pigments by Sun Chem. such as L74-1357 Yellow, L75-1331 Yellow andL75-2377 Yellow. Other examples include Pigment Yellow 1, Pigment Yellow3, Pigment Yellow 12, Pigment Yellow 13, Pigment Yellow 14, PigmentYellow 17, Pigment Yellow 65, Pigment Yellow 73, Pigment Yellow 74, CIPigment Yellow 93, CI Pigment Yellow 110, Pigment Yellow 151, PigmentYellow 117, Pigment Yellow 128, Pigment Yellow 138, Yellow Pigment 155,CI Pigment Yellow 213, CI Pigment Yellow 150, CI Pigment Yellow 219, CIPigment Yellow 220 and combinations thereof.

It is noteworthy that any of the pigments used in the inks of thepresent disclosure can, but do not necessarily have to, be self-dispersepigments. Self-disperse pigments can be a pigment functionalized with adispersant. The dispersant is typically prepared in a precursor form,and then the precursor is attached to the pigment to chemically modifythe surface of the pigment. In one embodiment, the dispersant can beattached to the pigment using various precursor materials, such aspara-aminobenzoic acids, isophthalic acids, tricarboxylic acids,carboxylic groups, sulfonylic groups, phosphates, oligomers, polymers,and isomers thereof, for example. Other precursors can also be used toattach to the pigment, as would be known by those skilled in the art.Other pigment types can also be used including encapsulated pigments anddisperse pigments.

Generally, any latex polymer commercially available can be used in theinks of the present disclosure including self-dispersed andfunctionalized latex polymers. Latex polymers can be prepared using anyof a number of methods known in the art, including but not limited toemulsion polymerization techniques where co-monomers are dispersed andpolymerized in a discontinuous phase of an emulsion. The latexes canalso be dispersions of polymer prepared by other techniques known tothose in the art. Monomers that are often used include ethyl acrylate;ethyl methacrylate; benzyl acrylate; benzyl methacrylate; propylacrylate; propyl methacrylate; iso-propyl acrylate; iso-propylmethacrylate; butyl acrylate; butyl methacrylate; hexyl acrylate; hexylmethacrylate; octadecyl methacrylate; octadecyl acrylate; laurylmethacrylate; lauryl acrylate;

hydroxyethyl acrylate; hydroxyethyl methacrylate; hydroxyhexyl acrylate;hydroxyhexyl methacrylate; hydroxyoctadecyl acrylate; hydroxyoctadecylmethacrylate; hydroxylauryl methacrylate; hydroxylauryl acrylate;phenethyl acrylate; phenethyl methacrylate; 6-phenylhexyl acrylate;6-phenylhexyl methacrylate; phenyllauryl acrylate; phenyllaurylmethacrylate; 3-nitrophenyl-6-hexyl methacrylate;3-nitrophenyl-18-octadecyl acrylate; ethyleneglycol dicyclopentyl etheracrylate; vinyl ethyl ketone; vinyl propyl ketone; vinyl hexyl ketone;vinyl octyl ketone; vinyl butyl ketone; cyclohexyl acrylate;methoxysilane; acryloxypropyhiethyldimethoxysilane; trifluoromethylstyrene; trifluoromethyl acrylate; trifluoromethyl methacrylate;tetrafluoropropyl acrylate; tetrafluoropropyl methacrylate;heptafluorobutyl methacrylate; iso-butyl acrylate; iso-butylmethacrylate; 2-ethylhexyl acrylate; 2-ethylhexyl methacrylate;iso-octyl acrylate; and iso-octyl methacrylate.

As stated previously, two or more of the above-described inks can beincluded together to form an ink set. In one embodiment, an ink set caninclude the cyan ink and the black ink. In another embodiment, the inkset can further include the magenta ink. In yet another embodiment, theink set can further include the yellow ink. In a further embodiment, theink set can further include both the magenta ink and the yellow ink.

In another embodiment, an ink set can include the cyan ink, the magentaink, and the yellow ink. In one embodiment, the ink set can furtherinclude the black ink.

In related embodiments, a system for printing images on low-porous ornon-porous media is provided. The system includes a low-porous ornon-porous media substrate and an ink set. The ink set can include thecyan ink and the black ink. In one embodiment, the ink-jet of the systemcan further include at least one of the magenta ink and the yellow ink.Alternatively, the ink set of the system can include the yellow ink, themagenta ink, and the cyan ink. In one embodiment, the system can furtherinclude the black ink.

The present disclosure also provides for methods of printing onlow-porous or non-porous media. In one embodiment, a method of printingon low-porous or non-porous media comprises ink-jetting an amount of inkfrom an ink set onto a low porous or non-porous media substrate. The inkset can include the cyan ink and the black ink. In one embodiment, theink set can further include at least one of the yellow ink or themagenta ink.

In another embodiment, a method of printing on low-porous or non-porousmedia comprises ink-jetting an amount of ink from an ink set onto a lowporous or non-porous media substrate. The ink set can include the cyanink, the magenta ink, and the yellow ink. In one embodiment, the ink setcan further include the black ink.

As shown in Example 12, the black inks of the invention were found tohave the surprising characteristic of having a lower L* (i.e. a darkerblack color) than identical inks having smaller amounts of latex orbeing devoid of latex. In other words, it was discovered that the L* ofthe black inks of the present invention can be decreased by increasingthe amount of the latex in the ink and without the addition of pigment.

The ink-jet ink compositions used in the ink sets, systems, and methodsof the present disclosure are typically prepared using an aqueousformulation or liquid vehicle which can include water, co-solvents,surfactants, buffering agents, biocides, sequestering agents, viscositymodifiers, humectants, binders, and/or other known additives. Typically,the ink-jet ink compositions of the present invention have a viscosityof between about 0.8 cps to about 15 cps, and in one embodiment, can befrom about 0.8 cps to about 8 cps. In one aspect, the liquid vehicle cancomprise from about 70 wt % to about 95 wt % of the ink-jet inkcomposition. The liquid vehicle typically comprises water and organicsolvent. In one embodiment, the liquid vehicle can comprise water andabout 1 wt % to about 70 wt % organic solvent. In another embodiment,the liquid vehicle can comprise water and about 5 wt % to about 50 wt %organic solvent.

Suitable co-solvents for use in the present disclosure include watersoluble organic co-solvents, but are not limited to, aliphatic alcohols,aromatic alcohols, diols, triols, glycol ethers, poly(glycol) ethers,lactams, formamides, acetamides, long chain alcohols, ethylene glycol,propylene glycol, diethylene glycols, triethylene glycols, glycerine,dipropylene glycols, glycol butyl ethers, polyethylene glycols,polypropylene glycols, amides, ethers, carboxylic acids, esters,organosulfides, organosulfoxides, sulfones, alcohol derivatives,carbitol, butyl carbitol, cellosolve, ether derivatives, amino alcohols,and ketones. For example, co-solvents can include primary aliphaticalcohols of 30 carbons or less, primary aromatic alcohols of 30 carbonsor less, secondary aliphatic alcohols of 30 carbons or less, secondaryaromatic alcohols of 30 carbons or less, 1,2-diols of 30 carbons orless, 1,3-diols of 30 carbons or less, 1,5-diols of 30 carbons or less,ethylene glycol alkyl ethers, propylene glycol alkyl ethers,poly(ethylene glycol) alkyl ethers, higher homologs of poly(ethyleneglycol) alkyl ethers, poly(propylene glycol) alkyl ethers, higherhomologs of poly(propylene glycol) alkyl ethers, lactams, substitutedformamides, unsubstituted formamides, substituted acetamides, andunsubstituted acetamides. Specific examples of co-solvents that areemployed in the practice of this disclosure include, but are not limitedto, 1,5-pentanediol, 2-pyrrolidone, ethoxylated glycerols such asLiponic ethoxylated glycerol 1 (EG-1) and Liponic ethoxylated glycerol 7(EG-7), 2-methyl-2,4-pentanediol, 2-methyl-1,3-propanediol,2-ethyl-2-hydroxymethyl-1,3-propanediol, diethylene glycol,3-methoxybutanol, propylene glycol monobutyl ether, and1,3-dimethyl-2-imidazolidinone. Co-solvents can be added to reduce therate of evaporation of water in the ink to minimize clogging or otherproperties of the ink such as viscosity, pH, surface tension, opticaldensity, and print quality. Various buffering agents can also beoptionally used in the ink-jet ink compositions of the presentdisclosure. Typical buffering agents include such pH control solutionsas hydroxides of alkali metals and amines, such as lithium hydroxide,sodium hydroxide, potassium hydroxide; citric acid; amines such astriethanolamine, diethanolamine, and dimethylethanolamine; and otherbasic or acidic components. If used, buffering agents typically compriseless than about 10 wt % of the ink-jet ink composition.

In another aspect of the present disclosure, various biocides can beused to inhibit growth of undesirable microorganisms. Severalnon-limiting examples of suitable biocides include benzoate salts,sorbate salts, commercial products such as NUOSEPT®, UCARCIDE™,VANCIDE®, and PROXEL™ and other known biocides. Typically, such biocidescomprise less than about 5 wt % of the ink-jet ink composition and oftenfrom about 0.05 wt % to about 2 wt %.

The inks of the present disclosure may also include one or moresurfactants may as are known by those skilled in the art of inkformulation. Non-limiting examples of such surfactants include alkylpolyethylene oxides, alkyl phenyl polyethylene oxides, polyethyleneoxide block copolymers, acetylenic polyethylene oxides, polyethyleneoxide (di)esters, polyethylene oxide amines, protonated polyethyleneoxide amines, protonated polyethylene oxide amides, substituted amineoxides, polyethylene oxide alkyl sulfonates, polyethylene oxide alkylsulfates, polyethylene oxide alkyl phosphates, and the like, as well asfluorocarbon and silicone surfactants.

EXAMPLES

The following examples illustrate the embodiments of the disclosure thatare presently best known. However, it is to be understood that thefollowing are only exemplary or illustrative of the application of theprinciples of the present disclosure. Numerous modifications andalternative compositions, methods, and systems may be devised by thoseskilled in the art without departing from the spirit and scope of thepresent disclosure. The appended claims are intended to cover suchmodifications and arrangements. Thus, while the present disclosure hasbeen described above with particularity, the following examples providefurther detail in connection with what are presently deemed to be themost practical and preferred embodiments of the disclosure.

Example 1 Low Pigment and High Latex Concentration Ink Formulations

Low pigment and high latex concentration inks were prepared according tothe formulations set forth in Table 1. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were also taken and arelisted in Table 1.

TABLE 1 Ingredients (%) Black Cyan Magenta Yellow Pigment Load (in wt %)1.25% 1.25% 2.25% 2.50% Latex Polymer 7.00% 7.00% 7.00% 6.00%2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00% 9.00%9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00% 2.00%surfactant Water Balance Balance Balance Balance ABS of 1:2500 0.2550.283 0.253 0.517 Dilution of Ink* *The ABS measurements are of the peakabsorbance which occurs at the following wavelengths or wavelengthranges: black ink - 500 nm; cyan ink - 610-630 nm; magenta Ink - 520-555nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 2 Low Pigment and Medium Latex Concentration Ink Formulations

Low pigment and medium latex concentration inks were prepared accordingto the formulations set forth in Table 2. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 2.

TABLE 2 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment1.25% 1.25% 2.25% 2.50% Load (in wt %) Latex Polymer 5.75% 5.75% 5.75%5.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.244 0.276 0.249 0.505 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 3 Low Pigment and Low Latex Concentration Ink Formulations

Low pigment and low latex concentration inks were prepared according tothe formulations set forth in Table 3. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 3.

TABLE 3 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment1.25% 1.25% 2.25% 2.50% Load (in wt %) Latex Polymer 4.50% 4.50% 4.50%4.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.234 0.269 0.239 0.49 Dilution of Ink * The ABS measurements are of thepeak absorbance which occurs at the following wavelengths or wavelengthranges: black ink - 500 nm; cyan ink - 610-630 nm; magenta Ink - 520-555nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 4 Medium Pigment and High Latex Concentration Formulations

Medium pigment and high latex concentration formulations were preparedaccording to the formulation set forth in Table 4. Absorbancemeasurements of a 1:2,500 dilution of each of the prepared inks weretaken and are also listed in Table 4.

TABLE 4 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment1.63% 1.63% 2.75% 3.00% Load (in wt %) Latex Polymer 7.00% 7.00% 7.00%6.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.312 0.354 0.301 0.604 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 5 Medium Pigment and Medium Latex Concentration Ink Formulations

Medium pigment and Medium latex concentration ink were preparedaccording to the formulations set forth in Table 5. Absorbancemeasurements of a 1:2,500 dilution of each of the prepared inks weretaken and are also listed in Table 5.

TABLE 5 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment1.63% 1.63% 2.75% 3.00% Load (in wt %) Latex Polymer 5.75% 5.75% 5.75%5.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.302 0.355 0.293 0.595 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 6 Medium Pigment and Low Latex Concentration Ink Formulations

Medium pigment and low latex concentration inks were prepared accordingto the formulations set forth in Table 6. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 6.

TABLE 6 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment1.63% 1.63% 2.75% 3.00% Load (in wt %) Latex Polymer 4.50% 4.50% 4.50%4.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.292 0.346 0.284 0.589 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 7 High Pigment and High Latex Concentration Ink Formulations

High pigment and high latex concentration inks were prepared accordingto the formulations set forth in Table 7. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 7.

TABLE 7 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment2.00% 2.00% 3.25% 3.50% Load (in wt %) Latex polymer 7.00% 7.00% 7.00%6.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.372 0.433 0.348 0.691 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 8 High Pigment and Medium Latex Concentration Ink Formulations

High pigment and medium latex concentration inks were prepared accordingto the formulations set forth in Table 8. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 8.

TABLE 8 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment2.00% 2.00% 3.25% 3.50% Load (in wt %) Latex Polymer 5.75% 5.75% 5.75%5.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.362 0.423 0.334 0.678 Dilution of Ink * The ABS measurements are ofthe peak absorbance which occurs at the following wavelengths orwavelength ranges: black ink - 500 nm; cyan ink - 610-630 nm; magentaInk - 520-555 nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 9 High Pigment and Low Latex Concentration Ink Formulations

High pigment and low latex concentration inks were prepared according tothe formulations set forth in Table 8. Absorbance measurements of a1:2,500 dilution of each of the prepared inks were taken and are alsolisted in Table 9.

TABLE 9 Ingredients (%) Black Cyan Magenta Yellow Equivalent Pigment2.00% 2.00% 3.25% 3.50% Load (in wt %) Latex Polymer 4.50% 4.50% 4.50%4.00% 2-pyrrolidone 16.00% 16.00% 16.00% 16.00% 2-methyl-1,3- 9.00%9.00% 9.00% 9.00% propanediol Polyethylene perfluoro 2.00% 2.00% 2.00%2.00% surfactant Water Balance Balance Balance Balance ABS of 1:2,5000.352 0.42 0.336 0.664 Dilution of Ink * The ABS measurements are of thepeak absorbance which occurs at the following wavelengths or wavelengthranges: black ink - 500 nm; cyan ink - 610-630 nm; magenta Ink - 520-555nm; yellow ink - 380-430 nm. The path length was 1 cm.

Example 10 Effects Of Latex And Pigment Concentrations On Chroma OnGlossy Non-Porous Media

Ink absorbance is generally determined by the amount of pigment in theink. The absorbance of the incremental latex loading is seen to be smallfrom these examples. Color ramps were prepared for each of the colordegree measures of 30 degree red, 40 degree red, 290 degree blue, and170 degree green on glossy non-porous media. The color ramps wereprinted using twenty-one ink levels per color such that all potentialcombinations of each color were tested for a total of 441 squares. Asnot all these combinations are realistic to use in printing, the datawas filtered to remove points using ink amounts beyond the systemlimits. Color measurements were made using a X-Rite Eye One iO. Colormeasurements were taken using D50 illuminant, 2 degree observer and 45/0geometry as specified by CIE standards. The remaining values were thenfiltered by hue angle. The largest values were selected and their chroma(C*) and L* were measured. The measurement values are shown in Table 10.

TABLE 10 Inks C* L* 30 degree red Example 1 80.5 49.4 Example 2 79.649.6 Example 3 76.9 49.8 Example 4 83.3 46.4 Example 5 81.5 47.5 Example6 80.0 48.8 Example 7 83.1 45.7 Example 8 82.3 46.8 Example 9 79.6 48.340 degree red Example 1 81.6 54.8 Example 2 83.0 52.6 Example 3 78.954.7 Example 4 83.6 51.8 Example 5 81.5 54.9 Example 6 78.6 56.3 Example7 84.1 51.7 Example 8 79.8 53.7 Example 9 77.0 55.4 290 degree blueExample 1 62.8 22.1 Example 2 63.4 21.3 Example 3 60.0 24.7 Example 464.0 21.0 Example 5 62.1 22.2 Example 6 60.1 22.3 Example 7 63.6 18.4Example 8 62.2 22.3 Example 9 54.0 23.8 170 degree green Example 1 81.943.2 Example 2 83.2 44.0 Example 3 80.8 45.6 Example 4 82.0 40.1 Example5 80.9 43.4 Example 6 77.1 42.4 Example 7 78.1 37.7 Example 8 76.6 44.4Example 9 73.9 46.2

The significance of the measurements is discussed in Example 11.

Example 11 Effects of Latex and Pigment Concentration on Chroma in MatteNon-Porous Media

Color ramps were prepared similarly to Example 10, except that the mediawas matte non-porous media. The color ramps were printed usingtwenty-one ink levels per color such that all potential combinations ofeach color were tested for a total of 441 squares. As in Example 10, notall these combinations are realistic to use in printing, the data wasfiltered to remove points using ink amounts beyond the system limits.Color measurements were made using a X-Rite Eye One iO. Colormeasurements were taken using D50 illuminant, 2 degree observer and 45/0geometry as specified by CIE standards. The remaining values were thenfiltered by hue angle. The largest values were selected and their chroma(C*) and L* were measured. The measurement values are shown in Table 11.

TABLE 11 Inks C* L* 30 degree red Example 1 77.5 49.2 Example 2 77.349.0 Example 3 76.4 49.0 Example 4 79.1 47.4 Example 5 77.5 47.2 Example6 76.9 48.8 Example 7 80.1 45.0 Example 8 77.5 47.7 Example 9 77.1 46.640 degree red Example 1 77.8 53.1 Example 2 76.3 54.7 Example 3 74.555.4 Example 4 78.9 53.4 Example 5 77.2 54.6 Example 6 75.2 54.3 Example7 78.6 52.0 Example 8 75.6 55.2 Example 9 74.6 55.3 290 degree blueExample 1 61.4 23.4 Example 2 61.0 23.2 Example 3 58.6 25.4 Example 460.2 21.1 Example 5 59.2 22.1 Example 6 59.1 20.8 Example 7 59.7 20.8Example 8 57.9 23.3 Example 9 58.0 22.1 170 degree green Example 1 78.745.8 Example 2 77.9 46.2 Example 3 76.4 46.3 Example 4 78.5 40.6 Example5 75.5 42.3 Example 6 72.4 43.3 Example 7 73.9 40.6 Example 8 73.5 43.7Example 9 72.0 42.6

The differences in chroma appreciated in Examples 10 and 11 aresignificant as these define the boundary of the color gamut, that is,the maximum range of colors that the printing system can achieve. Thisis a critical parameter that will determine if a printer is able toprint a job with certain color needs. Moreover, it is important torelate these figures with competitive analysis, which ultimately willdetermine which printing system is used. For example, when comparing toprofessional color palettes such as Pantone, these chroma valuesrepresented will determine which percentage of the colors can beaccurately represented (e.g. 80%).

Example 12 Effects of Latex and Pigment Concentration on Lightness inBlack Pigmented Inks

Six black inks were prepared using two different pigment concentrationsand three different latex concentrations. Each of the pigments wasprinted onto 3M ControlTac non-porous print media to form a 100% densityprinted block. The L* measurements of each of the inks printed blockswere measured with an X-rite colorimeter and are set forth below inTable 12.

TABLE 12 Wt % Black Wt % Latex Pigment L* Ink 1 6.0 1.6 9.3 Ink 2 4.01.6 12.1 Ink 3 2.0 1.6 14.9 Ink 4 6.0 2.0 9.3 Ink 5 4.0 2.0 11.8 Ink 62.0 2.0 15.3It was surprisingly discovered that the L* of the black ink decreased(i.e. a darker black was produced) when the latex concentration wasincreased without increasing the pigment concentration.

While the disclosure has been described with reference to certainpreferred embodiments, those skilled in the art will appreciate thatvarious modifications, changes, omissions, and substitutions can be madewithout departing from the spirit of the disclosure. It is thereforeintended that the invention be limited only by the scope of the appendedclaims.

1. An ink set for use in ink-jet printing, comprising: a cyan inkcomprising from 0.25 wt % to 3 wt % solids of a cyan pigment and from 4wt % to 15 wt % solids of a latex polymer, and wherein a 1:2,500dilution in water of the cyan ink has a UV absorbance of 0.048 to 0.592at its absorbance peak found at from 600 nm to 630 nm; and a black inkcomprising from 0.25 wt % to 3 wt % solids of a black pigment and from 4wt % to 15 wt % solids of a latex polymer, and wherein a 1:2,500dilution in water of the black ink has a UV absorbance of 0.04 to 0.468at about 500 nm.
 2. An ink set as in claim 1, wherein the ink setincludes a magenta ink comprising 0.75 wt % to 5 wt % solids of amagenta pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the magenta ink has a UVabsorbance of 0.068 to 0.468 at its absorbance peak found at from 520 nmto 555 nm.
 3. An ink set as in claim 2, wherein the magenta pigmentcomprises 2.25 wt % to 4 wt % solids of the magenta ink.
 4. An ink setas in claim 2, wherein the latex polymer comprises from 5 wt % to 8 wt %solids of the magenta ink.
 5. An ink set as in claim 1, wherein the inkset includes a yellow ink comprising 1 wt % to 4.5 wt % solids of ayellow pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the yellow ink has a UVabsorbance of 0.176 to 0.784 at its absorbance peak found at from 380 nmto 430 nm.
 6. An ink set as in claim 5, wherein the yellow pigmentcomprises 2.5 wt % to 4.5 wt % solids of the yellow ink.
 7. An ink setas in claim 5, wherein the latex polymer comprises 5 wt % to 8 wt %solids of the yellow ink.
 8. An ink set as in claim 1, wherein the latexpolymer present in at least one of the cyan or black inks is present inan amount of 5 wt % to 8 wt % by solids.
 9. An ink set as in claim 1,wherein the black ink comprises 1.25 wt % to 2 wt % solids of a blackpigment or the cyan ink comprises from 1.25 wt % to 2 wt % solids of acyan pigment.
 10. An ink set as in claim 1, wherein the presence of thesolids of a latex polymer increases the absorbance of the cyan ink orthe black ink at from 0.1% to 10% compared to an identical ink devoid ofthe solids of the latex polymer.
 11. An ink set as in claim 1, whereinthe L* of the black ink is lower than that of an identical black inkdevoid of the latex polymer.
 12. An ink set as in claim 1, wherein a1:2,500 dilution in water of the cyan ink has a UV absorbance of 0.16 to0.38 at its absorbance peak found at from 600 nm to 630, and wherein a1:2,500 dilution in water of the black ink has a UV absorbance of 0.16to 0.36 at about 500 nm.
 13. An ink set for use in ink-jet printing,comprising: a cyan ink comprising from 0.25 wt % to 3 wt % solids of acyan pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the cyan ink has a UV absorbanceof 0.048 to 0.592 absorbance at its absorbance peak found at from 610 nmto 630 nm; a magenta ink comprising from 0.75 wt % to 5 wt % solids of amagenta pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the magenta ink has a UVabsorbance of 0.068 to 0.468 at its absorbance peak found at from 520 nmto 555 nm; and a yellow ink comprising from 1 wt % to 4.5 wt % solids ofa yellow pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the yellow ink has a UVabsorbance of 0.176 to 0.784 at its absorbance peak found at from 380 nmto 430 nm.
 14. An ink set as in claim 13, wherein the magenta pigmentcomprises 2.25 wt % to 4 wt % solids of the magenta ink.
 15. An ink setas in claim 13, wherein the yellow pigment comprises 2.5 wt % to 4.5 wt% solids of the yellow ink.
 16. An ink set as in claim 13, wherein thecyan ink comprises from 1.25 wt % to 2 wt % solids of a cyan pigment.17. An ink set as in claim 13, wherein the latex polymer present in atleast one of the cyan, magenta, or yellow ink is present in an amount of5 wt % to 8 wt % by solids, and wherein the presence of the solids of alatex polymer increases the absorbance of the cyan, magenta, or yellowink at from 0.1% to 10% compared to an identical ink devoid of thesolids of the latex polymer.
 18. An ink set as in claim 13, wherein theink set further includes a black ink comprising from 0.25 wt % to 3 wt %solids of a black pigment and from 4 wt % to 15 wt % solids of a latexpolymer, and wherein a 1:2,500 dilution in water of the black ink has aUV absorbance of 0.04 to 0.468 absorbance at about 500 nm.
 19. An inkset as in claim 18, wherein the black pigment comprises from 1.25 wt %to 2 wt % solids of the black ink.
 20. An ink set as in claim 18,wherein the L* of the black ink is lower than that of an identical blackink devoid of the latex polymer.
 21. An ink set as in claim 13, whereina 1:2,500 dilution in water of the cyan ink has a UV absorbance of 0.16to 0.38 at its absorbance peak found at from 600 nm to 630, wherein a1:2,500 dilution in water of the magenta ink has a UV absorbance of 0.16to 0.36 at its absorbance peak found at from 520 nm to 555 nm, andwherein a 1:2,500 dilution in water of the yellow ink has a UVabsorbance of 0.38 to 0.68 at its absorbance peak found at from 380 nmto 430 nm.
 22. A method of printing on low-porous or non-porous media,comprising ink-jetting an amount of ink from an ink set onto a lowporous or non-porous media substrate, said ink set comprising: a cyanink comprising from 0.25 wt % to 3 wt % solids of a cyan pigment andfrom 4 wt % to 15 wt % solids of a latex polymer, and wherein a 1:2,500dilution in water of the cyan ink has a UV absorbance of 0.048 to 0.592absorbance at its absorbance peak found at from 610 nm to 630 nm; and ablack ink comprising from 0.25 wt % to 3 wt % solids of a black pigmentand from 4 wt % to 15 wt % solids of a latex polymer, and wherein a1:2,500 dilution in water of the black ink has a UV absorbance of 0.04to 0.468 absorbance at about 500 nm.
 23. A method as in claim 22,wherein the ink set further comprises at least one of a magenta ink or ayellow ink, said magenta ink comprising from 0.75 wt % to 5 wt % solidsof a magenta pigment and 4 wt % to 15 wt % solids of a latex polymer,and wherein a 1:2,500 dilution in water of the magenta ink has a UVabsorbance of 0.068 to 0.468 at its absorbance peak found at from 520 nmto 555 nm; and said yellow ink comprising from 1 wt % to 4.5 wt % solidsof a yellow pigment and 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the yellow ink has a UVabsorbance of 0.176 to 0.784 at its absorbance peak found at from 380 nmto 430 nm.
 24. A method of printing on low-porous or non-porous media,comprising ink-jetting an amount of ink from an ink set onto a lowporous or non-porous media substrate, said ink set comprising: a cyanink comprising from 0.25 wt % to 3 wt % solids of a cyan pigment and 4wt % to 15 wt % solids of a latex polymer, and wherein a 1:2,500dilution in water of the cyan ink has a UV absorbance of 0.048 to 0.592absorbance at its absorbance peak found at from 610 nm to 630 nm; amagenta ink comprising from 0.75 wt % to 5 wt % solids of a magentapigment and 4 wt % to 15 wt % solids of a latex polymer, and wherein a1:2,500 dilution in water of the magenta ink has a UV absorbance of0.068 to 0.468 at its absorbance peak found at from 520 nm to 555 nm;and a yellow ink comprising from 1 wt % to 4.5 wt % solids of a yellowpigment and 4 wt % to 15 wt % solids of a latex polymer, and wherein a1:2,500 dilution in water of the yellow ink has a UV absorbance of 0.176to 0.784 at its absorbance peak found at from 380 nm to 430 nm.
 25. Amethod as in claim 24, wherein the ink set further comprises a blackink, said black ink comprising from 0.25 wt % to 3 wt % solids of ablack pigment and from 4 wt % to 15 wt % solids of a latex polymer, andwherein a 1:2,500 dilution in water of the black ink has a UV absorbanceof 0.04 to 0.468 absorbance at 500 nm.